dusty deck

Old software (especially applications) which one is obliged to
remain compatible with, or to maintain. DP types call this
"legacy code", a term hackers consider smarmy and excessively
reverent. The term implies that the software in question is a
holdover from card-punch days. Used especially when referring
to old scientific and number crunching software, much of
which was written in Fortran and very poorly documented but is
believed to be too expensive to replace. See fossil;
compare crawling horror.